Getting the SQL query delegated by a derived view

Applies to: Denodo 7.0 , Denodo 6.0 , Denodo 5.5 , Denodo 5.0
Last modified on: 26 Mar 2018
Tags: JDBC data sources Combination ODBC data sources

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Content

When working with views created on top of JDBC and ODBC data sources, the Virtual DataPort query engine will push down SQL queries to the data sources to retrieve the data requested in the queries.

The information about the SQL query delegated by a view to any of these data sources is available in the execution trace of a query

To have the execution trace of a query available, when executing the query from a VDP administration tool Execution panel make sure that the "Execute with TRACE" option is selected. To get the execution trace of a query executed from a VQL shell add a “TRACE” clause at the end of any query.

Execute_with_trace.png

With these options selected, once the query finishes, to see the execution trace:

  1. Click on the "Execution Trace" button.

query_results.png

  1. From the Execution Trace window, on the left side a tree with the execution plan is displayed.
  2. Both for JDBC and ODBC wrappers, the bottom node of the execution plan for the branch associated to those data sources will be a JDBC route type of node. Click on this type of nodes to see the SQL query that gets delegated to the data sources.

execution_trace_left_side.png

  1. After selecting the node, the right side of the execution trace window shows information about the JDBC connection, including the query sent to the database with the "SQL sentence" label.

References

Virtual DataPort Administration Guide: Execution Trace of a Statement

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